Radio base station apparatus, mobile terminal device, and cell selecting method

Abstract

To provide a cell selecting method in which an optimal cell can be selected in the case of relay transmission. The cell selecting method includes: in a radio base station apparatus, determining a specified sub-frame including data for measuring reception quality in a mobile terminal device; and in a mobile terminal device, measuring first reception quality using a reference signal of the specified sub-frame transmitted from the radio base station apparatus and second reception quality using a reference signal of the specified sub-frame transmitted from the radio base station apparatus through a radio relay station apparatus, and transmitting the first reception quality and the second reception quality to the radio base station apparatus; and in the radio base station apparatus, selecting a cell to which the mobile terminal device is connected using the first reception quality and the second reception quality, and transmitting information on the selected cell to the mobile terminal device.

1 . A radio base station apparatus comprising:
 a sub-frame determination section configured to determine a specified sub-frame for measuring reception quality in a mobile terminal device;   a transmitting section configured to transmit information on the specified sub-frame; and   a cell selection determination section configured to select a cell to which the mobile terminal device is connected using a first reception quality measured value and a second reception quality measured value, the first reception quality measured value measured using a reference signal of the specified sub-frame transmitted from the radio base station apparatus to the mobile terminal device, the second reception quality measured value measured using a reference signal of the specified sub-frame transmitted from the radio base station apparatus to the mobile terminal device through a radio relay station apparatus, wherein   the specified sub-frame includes data, and the transmitting section is configured to transmit information on the selected cell to the mobile terminal device.   
     
     
         2 . The radio base station apparatus according to  claim 1 , wherein the specified sub-frame is a normal sub-frame. 
     
     
         3 . A radio base station apparatus comprising:
 a receiving section configured to receive a first reception quality measured value and a second reception quality measured value, the first reception quality measured value measured using a reference signal transmitted from the radio base station apparatus to a mobile terminal device, the second reception quality measured value measured using a reference signal transmitted from the radio base station apparatus to the mobile terminal device through a radio relay station apparatus;   a cell determination section configured to determine a cell to which the mobile terminal device is connected, by adding an offset value to the second reception quality measured value and comparing the second reception quality measured value with the first reception quality measured value; and   a transmitting section configured to transmit information on the determined cell to the mobile terminal device.   
     
     
         4 . A radio base station apparatus comprising:
 an offset value determination section configured to determine an offset value of a second reception quality measured value with respect to a first reception quality measured value, the first reception quality measured value measured using a reference signal transmitted from the radio base station apparatus to a mobile terminal device, the second reception quality measured value measured using a reference signal transmitted from the radio base station apparatus to the mobile terminal device through a radio relay station apparatus; and   a transmitting section configured to transmit information on the determined offset value to the mobile terminal device.   
     
     
         5 . The radio base station apparatus according to  claim 4 , wherein the offset value determination section is configured to determine the offset value using the second reception quality measured value transmitted from the mobile terminal device. 
     
     
         6 . The radio base station apparatus according to  claim 4 , wherein the transmitting section is configured to transmit an absolute value of the offset value as the information on the offset value. 
     
     
         7 . The radio base station apparatus according to  claim 4 , wherein the transmitting section is configured to transmit a difference value between an offset value transmitted immediately before and an offset value currently transmitted, as the information on the offset value. 
     
     
         8 . A mobile terminal device comprising:
 a receiving section configured to receive information on a specified sub-frame for measuring reception quality;   a reception quality measuring section configured to measure first reception quality using a reference signal of the specified sub-frame transmitted from a radio base station apparatus, and to measure second reception quality using a reference signal of the specified sub-frame transmitted from the radio base station apparatus through a radio relay station apparatus; and   a transmitting section configured to transmit the measured value of the first reception quality and the measured value of the second reception quality to the radio base station apparatus.   
     
     
         9 . A mobile terminal device comprising:
 a reception quality measuring section configured to measure first reception quality using a reference signal transmitted from a radio base station apparatus, and to measure second reception quality using a reference signal transmitted from the radio base station apparatus through a radio relay station apparatus; and   a cell determination section configured to select a cell to which the mobile terminal device is connected, using information on an offset value of the measured value of the second reception quality with respect to the measured value of the first reception quality, the offset value notified from the radio base station apparatus.   
     
     
         10 . The mobile terminal device according to  claim 9 , wherein the information on the offset value is an absolute value of the offset value. 
     
     
         11 . The mobile terminal device according to  claim 9 , wherein the information on the offset value is a difference value between an offset value transmitted immediately before and an offset value currently transmitted. 
     
     
         12 . A cell selecting method comprising the steps of:
 in a radio base station apparatus, determining a specified sub-frame including data for measuring reception quality in a mobile terminal device, and transmitting information on the specified sub-frame;   in the mobile terminal device, receiving the information on the specified sub-frame, measuring first reception quality using a reference signal of the specified sub-frame transmitted from the radio base station apparatus, while measuring second reception quality using a reference signal of the specified sub-frame transmitted from the radio base station apparatus through a radio relay station apparatus, and transmitting the measured value of the first reception quality and the measured value of the second reception quality to the radio base station apparatus; and   in the radio base station apparatus, selecting a cell to which the mobile terminal device is connected using the measured value of the first reception quality and the measured value of the second reception quality, and transmitting information on the selected cell to the mobile terminal device.   
     
     
         13 . A cell selecting method comprising:
 in a mobile terminal device, measuring first reception quality using a reference signal transmitted from a radio base station apparatus to the mobile terminal device, while measuring second reception quality using a reference signal transmitted from the radio base station apparatus to the mobile terminal device through a radio relay station apparatus, and transmitting the measured value of the first reception quality and the measured value of the second reception quality to the radio base station apparatus; and   in the radio base station apparatus, determining a cell to which the mobile terminal device is connected, by adding an offset value to the second reception quality measured value and comparing the second reception quality measured value with the first reception quality measured value, and transmitting information on the determined cell to the mobile terminal device.   
     
     
         14 . A cell selecting method comprising:
 in a radio base station apparatus, determining an offset value of a second reception quality measured value measured using a reference signal transmitted from the radio base station apparatus to a mobile terminal device through a radio relay station apparatus with respect to a first reception quality measured value measured using a reference signal transmitted from the radio base station apparatus to the mobile terminal device, and transmitting information on the determined offset value to the mobile terminal device; and   in the mobile terminal device, measuring the first reception quality and measuring the second reception quality, and selecting a cell to which the mobile terminal device is connected, using the information on the measured value of the first reception quality, the measured value of the second reception quality, and the offset value.